Polyester imides of trimellitic anhydride



United States Patent 3,274,159 POLYESTER IMIDES OF TRINELLITIC ADRIDE Rudolph W. Kluiher, Bernardsville, N.J., assignor to Union Carbide (Jorporation, a corporation of New York No Drawing. Filed Jan. 7, 1963, Ser. No. 249,611

4 Claims. (Cl. 260-75) The invention relates to polyester imides of trimellitic anhydride and to method for preparation thereof.

Polyester imides of the present invention have the general formula wherein D and D are individually selected from (A) Divalent hydrocarbon radicals wherein the bonding carbon atoms are saturated and have at least one hydrogen atom attached thereto, and

(B) Divalent hydrocarbon-ether radicals containing as many as 5 internal ether oxygen atoms wherein each ether oxygen atom is attached to saturated carbon atoms each of which has at least one hydrogen atom attached thereto and wherein each oxygen atom is separated from another oxygen atom by at least two carbon atoms; and x is an integer such that the polyester imide has a reduced viscosity, measured at 50 C. as a 0.2 gram sample in 100 milliliters of p-chlorophenol, of from about 0.4 to about 20.

One of D and D in Formula I above can be selected from (A) or (B). Or, both D and D can be selected from either (A) or (B); in this event D and D can be the same or different radicals of the group (A) or (B).

D and/ or D selected from the hydrocarbon radical group (A), can be, for example, alkylene groups having the general formula such as methylene, ethylene, trimethylene, propylene, butylene, amylene, hexamethylene, heptamethylene, octarnethylene, nonamethylene, decamethylene, undecamethylene, dodecamethylene, tridecylene, tetradecylene, pentadecylene, hexadecylene, heptadecylene, octadecylene, nonadecylene, eicosylene, and isomeric forms and higher homologs thereof;

divalent alicyclic groups such as 1,2-, 1,3-, and 1,4- cyclohexylene, 1,2- and 1,3-cyclopentylene, and 1,2- and 1,3-cyclobutylene;

and divalent aralkylene groups such as ortho, meta, and para xylylene:

And, D and/ or D selected from hydrocarbon-ether radical group (B), can be, for example, the above listed hydrocarbon radicals containing as many as five internal ether oxygen atoms wherein each oxygen atom is attached to saturated carbon atoms each of which has at least one hydrogen atom attached thereto and wherein each oxygen atom is separated from another ether oxygen atom by at least two carbon atoms.

Certain polyester imides have been prepared heretofore by the reaction of acid anhydrides and aminoalcohols. Aminoalcohol-based polyester imides, however, are limited in variety by the relatively few aminoalcohols available and are limited in utility by characteristically low melting points and poor strength properties.

It has now been discovered that theromplastic polyester imides containing aromatic nuclei and having high use temperature characteristics can be prepared in wide variety by causing to react aliphatic glycols and bistrimelli-timidates at an elevated temperature, preferably in the presence of a catalytic amount of a transesterification catalyst.

The reaction to the polyester imides proceeds according to the following scheme wherein D in Formula II and D in Formula III have the significance given in Formula I above.

o 0 ll 0 o ND1N H0-D2OH R000 c 0 0 R C C l II II o 0 bis-trimellitimidate HOR (IV) The radical R in Formulas II and IV can be a saturated aliphatic group, i.e., alkyl or cycloalkyl, containing from 1 to 6 carbon atoms inclusive, such as, for example, methyl, ethyl, propyl, butyl, pentyl, hexyl, and isomeric forms thereof, and cyclohexyl. It is desirable that the alcohol by-product, HOR (IV), be the most volatile component in the system so as to allow efficient removal from the polymerization system. Preferred is a bis-trimellitimidate (II) wherein R is methyl; in this case methyl alcohol will be the alcohol by-product.

The bis-trirnellitimidates (II) are prepared, in general, by causing to react trimellitic anhydrjde, which has the structural formula:

I HOOG- and a diprimary diamine having the structural formula: H ND NH (VI) at a temperature above about 25 C. to form a bis-trimellitimide, and esterifying the bis-trimellitimide, or preferably the corresponding bis-trimellitimidoyl chloride, with a primary alcohol having the structural formula HOR (IV), wherein D has the significance given in Formula I above.

The amount of the glycol reactant (III) used is usually in excess of stoichiometric proportions when no solvent is employed in the polymerization reaction. Generally about a 10 percent by weight excess of glycol is desirable for efiicient reaction, although excesses of up to percent by weight over the stoichiometric proportions can be used with suitable rates of reaction and with resultant production of high molecular weight polymers.

Preferred as the glycol reactant (III) is an alpha, omega-glycol or an alpha,omega-(glycol-ether) having the formula I wherein D of Formula III above is equal to CH Y CH wherein Y is selected from (VII) (a) divalent radical of the formula -(CH wherein n is an integer from 0 to 8 inclusive; (b) divalent ether radical of the formula where n is an integer from 1 to 3 inclusive; and temperature of about 175 C. or the melting point of the (c) divalent ether radical of the formula highest melting reactant or product as ghe minimgm 1gear tion temperature. It has been oun owever, t at ca- (CH2O C3H6 OCH2) ing of the reactants above about 260 C. causes some Particularly desirable specific alpha,-omega-glycols are 5 d iti f th polyester imide, L y y 1,3-iIiII1ethl/1eI1e g y 1,4-tetYa- The reaction can also be conducted in the presence of methylene y L -p y y a solvent. When a solvent medium is used, the solvent methylene glycol, 3-methylpentane 1,5-dio1, and 1,l0-deca should be in an inert organic liquid having a boiling point methylene glycol. of above about 175 C. at atmospheric pressure. Useful Particularly desirable specific alpha,omega-(glycol- 10 solvents are, for example, a-chloronaphthalene, o-dichloethers) are bis-(2-hydroxyethyl)ether, bis-(4-hydroXyrobenzene and the like. When a solvent is used it is butyl)ether, and the bis(2-hydroxyethyl)ether of propylsimilarly preferred that temperatures above 260 C. not

one glycol. be employed so as to avoid decomposition of the polymer. When these alpha,omega-glycols and alpha,omega- With the use of a solvent, stoichiometric amounts of (glycol-ethers) are employed the exchange reaction proglycol and bis-trimellitimide are preferably used in order ceeds most readily and with fewer side reactions, thus to produce polymers having highest molecular weights. reducing the time required for completion of polymeriza- Reaction is carried out for a period varying with the tion and increasing the molecular weight of the final reaction vessel, degree of agitation, quantities of reproduct. actants and proportions of reactants used and is in part The bis-trimellitimidate reactant (II) is preferably a determined by the desired end use properties of the polycompound having the formula: mer. Longer reaction times at a given reaction temo o perature for example, produce higher molecular weight ll ll polymers. Ordinarily reaction to a polyester imide of the desired molecular weight (reduced viscosity of about 0.4 to about 20, measured as described above) takes place N GH YICH2 N within 0.5 to 2 hours but longer or shorter times are equal- ROOC 1y feasible.

Atmospheric pressures are most conveniently employed 0 O and since sub-atmospheric or super-atmospheric pressures (V do not appear to have any effect on reaction rate or polyh i D f F l VI above i equal t mer product obtained use of atmospheric pressure is preferred.

CH2"'Y1CH2 During polymerization and after the initial transesteriand wherein Y has the significance given for Y in Forfication ire-action, erg. about 30 minutes after the start of mula VII above, and R has the significance given in reaction, a vacuum is applied to the system to remove Formula II above. from the reaction mass the excess glycol and alcohol Particularly desirable specific bis-trimellitimidates are byproduct. Reaction is continued in this manner until dimethyl N,N-hexamethylene-bis-trimellitimidate, wherea polyester imide of the desired molecular weight is obin Y contains 4 carbon atoms and R is methyl; dimethyl tained. Convenient periodic determinations of melt vis- N,N'ethylene-bis-trimellitimidate wherein Y is represent- 40 cosity or reduced viscosity can be used to follow progress ative of a bond between adjacent carbon atoms and R is of the reaction. The polymeric product is then cooled methyl; dihexyl N,N-hexamethylene-bis-trimellitimidate and used directly from the reaction mixture without wherein Y contains 4 carbon atoms and R contains 6 purification or other work-up. carbon atoms; and dimethyl N,N-[bis-(3-propyl ether)] As discussed above, the polymerization reaction can bis-trimellitimid-ate wherein Y contains 4 carbon atoms be conducted without use of a catalyst. However, transand one ether oxygen atom and R is methyl; and dimethyl esterification proceeds much more rapidly in the presence N,N'-propylene-bis-trimellitimidate wherein Y contains 1 of a catlyst and polymers of higher molecular weight are carbon atom and R is methyl. obtained. It is preferred, therefore that the reaction The preferred polyester imide, therefore, has the genmixture contain a catalytic amount i.e., up to about 0.5 eral formula: part of Weight, of a conventional transesterification catai i J 0 0 X (I wherein Y and Y have the significance given in Formula lyst. Useful catalysts in the invention are the oxides and VIII above and x has the significance given in Formula I hydroxides of metals of Groups IA, IIA, IIIA, IVA, VA, above, it being noted that Y and Y can be members of VIB, VIIB, AND VIIIB of the Deming Periodic Table the same group, i.e., a hydrocarbon radical group or hyas published in the Handbook of Chemistry and Physics, drocarbon-ether radical group, or of different groups, and 30th edition, page 312. Metal oxides and hydroxides dewhether from the same or different groups Y and Y can serving of special mention as catalysts herein are lithium be the same or different radicals. oxide, lithium hydroxide, sodium oxide, sodium hydrox- To effect reactlon of the glycol and bis-trimellitimidate ide, potassium oxide, potassium hydroxide, magnesium a mixture thereof is heated. Usually a temperature of oxide, magnesium hydroxide, calcium oxide, calcium hyat least 175 C. is necessary to obtain polymerization to a droxide, barium oxide, barium hydroxide ferric hynormally solid polymeric product even where both the droxide, ferric oxide, cobalt oxide, cobalt hydroxide zinc reactants melt below 175 C. Of course, systems starting oxide, zinc hydroxide, cadmium oxide, cadmiurri hywith higher melting reactants require higher melt reaction droxide, and the like. Other useful trans-esterification temperatures. It 1s preferred, therefore, when carrying catalysts are the monobasic and dibasic acid salts of the out the polymerization reaction in a melt to'employ a aforementioned metals, especially the lower aliphatic monobasic acid salts of these metals, e.g. those having up to 4 carbon atoms inclusive such as the acetate, propionate and butyrate salts of lithium, sodium, potassium,

tallizing the precipitate from toluene, 30.6 grams of product having a melting point of 165-167 C.

The structure of this bis-trimellitimidate was 0 0 H II o o N-CHzCHzCHgOHzCHgCH- N HaCOOC- ooocn, ll t 0 0 magnesium, calcium, iron, cobalt, nickel, cadmium, mercury, aluminum, germanium, tin and lead and the lower aliphatic dibasic acid salts of metals in the above enumerated groups, e.g., those having up to 10 carbon atoms inclusive, such as the oxalates, malonates, succinates, glutarates, adipates, pimelates, suberates, azelates and sebacates of lithium, sodium, potassium, magnesium, calcium, iron, cobalt, nickel, cadmium, mercury, aluminum, germanium, tin and lead. Still other trans-esterification catalysts especially deserving of mention are the ortho esters of titanium such as tetrabutyl titan-ate and trialkyl B. Preparation of polyester imide of trimellitic anhydride Five parts of the bis-trimellitimidate prepared in A and 2 parts of 1,4-tetramethylene glycol were heated to 200 C. at atmospheric pressure until they melted. One drop (0.5 part) of tetrabutyl titanate was added. After fifteen minutes of heating at 200 C. and at atmospheric pressure to being about ester exchange the pressure was reduced to 0.3 mm. Hg. Heating at 200 C. was continued for an hour after which time the temperature was raised to 250 C. to melt the crystalline polymer. Heattitanium halides such as triisopropyl titanium chloride, ing was Continued under Vacuum additional half and p-toluene sulfonic acid.

The following examples illustrate the invention, but should not be construed as being limitative thereof. All

hour. The polymer was then removed mechanically from the reaction vessel.

The polymer had the repeating unit parts and percentages are by weight unless otherwise mentioned.

EXAMPLE I A. Preparation of the bis-trimellitimidate and a reduced viscosity of 0.88 measured at 61.4 C. as a 0.2 gram sample in 100 milliliters of p-chlorophenol. This polymer was readily drawn into tough crystalline fibers having a melting point of 240 C.

EXAMPLE 2 Five parts of dimethyl N,N'-hexamethylene-bis-trimellitimidate, 2 parts of diethylene glycol, and .05 part of tetrabutyl titanate were heated at 200 C. and atmospheric pressure for minutes. The pressure was then reduced to 0.3 mm. Hg and polymerization continued for 18 hours. The polymer was separated as in Example 1.

The polymer had the repeating unit imide, was 108 grams. Forty seven grams of the diimide diacid was stirred into 150 milliliters of toluene and 98 milliliters of thionyl chloride was added. The mixture was heated at reflux with stirring for three hours. The thionyl chloride which had not reacted with the N,N- 'hexamethylene-bis-trimellitimide to form the correspondand a reduced viscosity of 0.55 measured at 53 C. as a 0.2 gram sample in 100 milliliters of p-chlorophenol.

This polymer was readily drawn into tough, non-crystalline fibers.

EXAMPLE 3 Five parts of dimethyl N,N-a,a-diaminodipropylether ing diacid Chloride was removed y distillatioll- Altar bis-trimellitimidate and 2 parts of hexamethylene glycol excess thionyl chloride was removed, 100 milliliters of a 50 percent by volume methanol-toluene mixture was added to the reaction flask. The addition caused the precipitation of dimethyl N,N-hexamethylene=bis-trimelwere heated to 200 C. and .05 part tetrabutyl titanate was added. Heating at 200 C. and atmospheric pressure was continued for 30 minutes, then the pressure was reduced to about 0.3 mm. Hg to aid in removal of the litimidate. There was obtained, after drying and recrysalcohol by-product and excess glycol. Heating at 200 C.

7 8 was continued for 4 hours. The polymer was separated EXAMPLE 11 as in Example 1. Examples 1-10 are duplicated but employing no cata- The polymer had the repeating unit lyst. A normally solid polymer is obtained in each case.

0 II II o 0 ll o and a reduced viscosity of 0.62 measured at 61 C. as a What is claimed is: 0.2 gram sample in 100 milliliters of p-chlorophenol. 15 1. Polyester imide having the general formula:

O 0 l l II II 0 O x This polymer was tough and flexible, and had a tensile wherein Y and Y are individually selected from the modulus of 225,000 and a glass transition temperature group consisting of (T of 61 C. (a) divalent radical of the formula (CH EXAMPLES 4-10 wherein n is an integer from 0 to 8, inclusive;

A variety of polymers were prepared by the procedure (b) divalent ether radical of the formula of Example 1. Their properties were determined. Table -(CH O(CH I records the data collected for these examples. Where n is an integer from 1 to 3 inclusive;

(c) divalent ether radical of the formula TABLE I (CH OC H OCH Tensile Yield and x is an integer such that the polyester imide has a Polymers of Y1(u) Y2(u) g Moduhls Strength reduced viscosity, measured at 50 C. as a 0.2 gram example at 2 at 1 sample in 100 milliliters of p-chlorophenol, of from 40 0.4 to about 20.

22. Polyester imide claimed in claim 1 wherein Y is CH 115 320,000 8,400 5 15 312 "@0600 "r500 (CH2)* and Y2 (CH2)4 h on y 1 3. Polyester imide claimed in claim 1 w erein Y is CH so 305, 000 6,800 9 -g 323,838 Z 288 -(CH CH OCH CH and Y 1s (CH y 1 10 0H2)l-- 0H)-- 45 211,000 4,100 gggfiiggfiggg; Wherem Y 15 Unitsrefer to Formula References Cited by the Examiner Glass transition temperature, tensile modulus, and yield UNITED STATES PATENTS strength were determined on an Instron testing machine. 2,048,778 7 /1936 Bmbakelet aL 260 75 The polyester imides of this invention can be injection 2 954 3 4 9 19 0 Coleman et 1 26O 75 and compression molded onto numerous articles useful 3,182,073 5 /1965 Loncrini 260 75 where toughness is a prime requisite. They can also be extruded into films and fibers of great toughness. These FOREIGN T N polyester imides have good high temperature use prop- 570,358 7/1945 Great Bntalllerties and good weathering characteristics which make SAMUELH BLECH Primal? Examiner them useful, for example, as outdoor wire insulation material. LOUISE P. QUAST, Examiner. 

1. POLYESTER IMIDE HAVING THE GENERAL FORMULA: 